Works of art worth hundreds of thousands of pounds are missing from British embassies and other official buildings around the world, according to a report published in The Times. At least 50 paintings from the Government Art Collection are unaccounted for, according to the latest audit. None was insured and some are known to have been stolen but more than half the total simply disappeared.

Some of the embassies mentioned are Ankara, Tripoli and Buenos Aires where in 2001 five oils worth £240,000 were stolen from the temporary residence of the Ambassador.

Jeremy Hunt, the Shadow Culture Secretary, has called on the Culture Minister Andy Burnham, to tighten security. "When the whole country is desperately trying to raise money to keep Titian's Diana and Actaeon painting, it is outrageous that the Government can't even look after the paintings we do have," he said. "The Department for Culture, Media and Sport needs to get it together on a problem that has been going on for too long."

The Government Art Collection contains more than 13,500 works stretching from the 16th century to the present day and includes some of the world's greatest artists. It receives an annual grant of £500,000, of which about half is spent buying and commissioning art to send to foreign missions to "show the vibrancy and variety of British artistic life and heritage".

The collection has never been valued but is likely to be worth more than £100 million. In 1988 its value was estimated by its curator at more than £30 million. Since then the collection has expanded and art prices rocketed.

Among the missing paintings are Beach Scene, by Abraham van Beyeren, considered one of the world's finest still life painters, and Capri Sunrise, Frederic, Lord Leighton, president of the Royal Academy from 1878 to 1896.

Beach Scene was reported stolen from the British embassy in Ankara in 1970. Capri Sunrise was recorded as destroyed at the British Embassy in Berlin during the Second World War but it reappeared in 2000 at a Christie's auction, where it sold for £102,000.

Also presumed stolen are works by the 18th-century landscape painter Julius Caesar Ibbetson and Frances Hodgkins and Carel Weight, two leading lights of the British Modern movement, who taught David Hockney and Sir Peter Blake.

Nowhere, it seems, is safe. In the 1990s paintings went missing from the Royal Courts of Justice, the main building of the Ministry of Defence and the collection's store.

A landscape by the renowned Scottish colourist, John Duncan Fergus-son, whose work regularly fetches six figures at auction, was last seen hanging on the walls of the residence of the Commander-in-Chief of the Allied Forces in Fontainebleau in 1967.

Other lost works include five prints of English scenes that were to be shipped back from the British Embassy in Tripoli in Libya but were reported missing by embassy staff in 2000.

Last February two paintings worth £82,000 were taken from Somerset House, London. They have since been recovered, the only stolen pieces recovered in the past 15 years. Leslie Churchill, 58, has pleaded guilty to the theft.

A spokesman for the DCMS, said: "There are more than 13,500 works of art in the Government Art Collection's holdings. The GAC undertakes audits of its holdings and these occasionally show that works are not in their previously recorded locations. However, after extensive searches many of these subsequently turn up."